Investigation into the effect of Y, Yb doping in Ba2In2O5: determination of the solid solution range and co-doping with phosphate

In this paper we examine the effect of Y, Yb doping in Ba2In2O5, examining the solid solution range and effect on the conductivity and CO2 stability. The results showed that up to 35% Y, Yb can be introduced, and this doping leads to an introduction of disorder on the oxygen sublattice, and a corresponding increase in conductivity. Further increases in Y, Yb content could be achieved through co-doping with phosphate. While this co-doping strategy led to a reduction in the conductivity, it did have a beneficial effect on the CO2 stability, and further improvements in the CO2 stability could be achieved through La and P co-doping

Centroidal bases in graphs

We introduce the notion of a centroidal locating set of a graph $G$, that is, a set $L$ of vertices such that all vertices in $G$ are uniquely determined by their relative distances to the vertices of $L$. A centroidal locating set of $G$ of minimum size is called a centroidal basis, and its size is the centroidal dimension $CD(G)$. This notion, which is related to previous concepts, gives a new way of identifying the vertices of a graph. The centroidal dimension of a graph $G$ is lower- and upper-bounded by the metric dimension and twice the location-domination number of $G$, respectively. The latter two parameters are standard and well-studied notions in the field of graph identification. We show that for any graph $G$ with $n$ vertices and maximum degree at least~2, $(1+o(1))\frac{\ln n}{\ln\ln n}\leq CD(G) \leq n-1$. We discuss the tightness of these bounds and in particular, we characterize the set of graphs reaching the upper bound. We then show that for graphs in which every pair of vertices is connected via a bounded number of paths, $CD(G)=\Omega\left(\sqrt{|E(G)|}\right)$, the bound being tight for paths and cycles. We finally investigate the computational complexity of determining $CD(G)$ for an input graph $G$, showing that the problem is hard and cannot even be approximated efficiently up to a factor of $o(\log n)$. We also give an $O\left(\sqrt{n\ln n}\right)$-approximation algorithm

Path coverings of the vertices of a tree

AbstractConsider a collection of disjoint paths in graph G such that every vertex is on one of these paths. The size of the smallest such collection is denoted i(G). A procedure for forming such collections is established. Restricting attention to trees, the range of values for the sizes of the collections obtained is examined, and a constructive characterization of trees T for which one always obtains a collection of size i(T) is presented

Efficient domination in knights graphs

The influence of a vertex set S ⊆V(G) is I(S) = Σv∈S(1 + deg(v)) = Σv∈S |N[v]|, which is the total amount of domination done by the vertices in S. The efficient domination number F(G) of a graph G is equal to the maximum influence of a packing, that is, F(G) is the maximum number of vertices one can dominate under the restriction that no vertex gets dominated more than once. In this paper, we consider the efficient domination number of some finite and infinite knights chessboard graphs

Queen\u27s domination using border squares and (\u3ci\u3eA\u3c/i\u3e,\u3ci\u3eB\u3c/i\u3e)-restricted domination

In this paper we introduce a variant on the long studied, highly entertaining, and very difficult problem of determining the domination number of the queen\u27s chessboard graph, that is, determining how few queens are needed to protect all of the squares of a k by k chessboard. Motivated by the problem of minimum redundance domination, we consider the problem of determining how few queens restricted to squares on the border can be used to protect the entire chessboard. We give exact values of border-queens required for the k by k chessboard when 1≤k≤13. For the general case, we present a lower bound of k(2-9/2k-√(8k2-49k+49)/2k) and an upper bound of k-2. For k=3t+1 we improve the upper bound to 2t+1 if 3t+1 is odd and 2t if 3t+1 is even. We generalize this problem to (A,B)-restricted parameters for vertex subsets A and B of V(G) where, for example, one must use only vertices in A to dominate all of B. Defining upper and lower parameters for independence, domination, and irredundance, we present a generalization of the domination chain of inequalities relating these parameters

On minimum dominating sets with minimum intersection

AbstractIn the developing theory of polynomial/linear algorithms for various problems on certain classes of graphs, most problems considered have involved either finding a single vertex set with a specified property (such as being a minimum dominating set) or finding a partition of the vertex set into such sets (for example, a partition into the maximum possible number of dominating sets). Alternatively, one might be interested in the cardinality of the set or the partition. In this paper we introduce an intermediate type of problem. Specifically, we ask for two minimum dominating sets with minimum intersection. We present a linear algorithm for finding two minimum dominating sets with minimum possible intersection in a tree T, and we show that simply determining whether or not there exist two disjoint minimum dominating sets is NP-hard for arbitrary bipartile graphs

Open-independent, Open-locating-dominating Sets

A distinguishing set for a graph G = (V, E) is a dominating set D, each vertex $v \in D$ being the location of some form of a locating device, from which one can detect and precisely identify any given "intruder" vertex in V(G). As with many applications of dominating sets, the set $D$ might be required to have a certain property for <D>, the subgraph induced by D (such as independence, paired, or connected). Recently the study of independent locating-dominating sets and independent identifying codes was initiated. Here we introduce the property of open-independence for open-locating-dominating sets

Theoretical aspects of the study of top quark properties

We review some recent theoretical progresses towards the determination of the top-quark couplings beyond the standard model. We briefly introduce the global effective field theory approach to the top-quark production and decay processes, and discuss the most useful observables to constrain the deviations. Recent improvements with a focus on QCD corrections and corresponding tools are also discussed.Comment: 8 pages, 6 figures. Based on plenary talk given at LHCP2017, Shanghai, 15-20 May 201